fix(shared): restore cache-paths subpath export (required at runtime)

Reverts the previous "keep cache-paths internal" change, which broke the
Playground Integration Tests with ERR_PACKAGE_PATH_NOT_EXPORTED. The export IS
load-bearing on a path the earlier verification missed: dev-playground runs its
server via `tsx` under the `development` export condition, so @databricks/appkit
resolves to SOURCE, whose `import "shared/cli/commands/cache-paths"` is a bare
cross-package specifier that tsx resolves through shared's package.json exports
map at runtime — tsconfig `paths` do not apply there. Without the export the
server never boots and Playwright times out.

Re-add the tsdown entry (which regenerates the export) with a comment
explaining the runtime dependency so it isn't dropped again. The export is
monorepo-internal only: shared is private and appkit bundles it inline
(noExternal), so it never reaches published-appkit consumers. Verified by
booting the dev-playground server under the development condition (starts
clean, no export error).

xavier loop: iteration 8 -- restore runtime-required cache-paths export

Co-authored-by: Isaac
Signed-off-by: Atila Fassina <atila@fassina.eu>

Author: atilafassina

packages/shared/package.json

@@ -15,6 +15,10 @@
       "development": "./src/cli/index.ts",
       "default": "./dist/cli/index.js"
     },
+    "./cli/commands/cache-paths": {
+      "development": "./src/cli/commands/cache-paths.ts",
+      "default": "./dist/cli/commands/cache-paths.js"
+    },
     "./package.json": "./package.json"
   },
   "scripts": {
@@ -35,6 +39,7 @@
     "exports": {
       ".": "./dist/index.js",
       "./cli": "./dist/cli/index.js",
+      "./cli/commands/cache-paths": "./dist/cli/commands/cache-paths.js",
       "./package.json": "./package.json"
     }
   },

packages/shared/tsdown.config.ts

@@ -2,7 +2,17 @@ import { defineConfig } from "tsdown";
 
 export default defineConfig({
   name: "shared",
-  entry: ["src/index.ts", "src/cli/index.ts"],
+  entry: [
+    "src/index.ts",
+    "src/cli/index.ts",
+    // Node-only path resolvers. Needs its own entry (→ generated
+    // "./cli/commands/cache-paths" export) because appkit imports it as a bare
+    // cross-package specifier that tsx resolves via shared's exports map at
+    // runtime (dev-playground's `development`-condition source run) — tsconfig
+    // paths don't apply there. Kept OUT of the client-safe root barrel because
+    // it imports node:path (would break the docs client webpack bundle).
+    "src/cli/commands/cache-paths.ts",
+  ],
   outDir: "dist",
   minify: false,
   format: "esm",